Drosophila body plan development Flashcards
What activates segmentation genes?
Pair-rule genes
In how many transverse stripes are segmentation genes expressed?
14 (one for each parasegment)
T/F: engrailed is a segmentation gene
True
T/F: blastoderm remains syncytial during pair-rule expression
False (cellularization happens)
What is a selector gene?
A gene that confers an identity on a region or regions
T/F: engrailed expression is temporary
False (permanent)
In how many lines of cells is engrailed expressed, and where in the parasegment?
One line of cells in the anterior margin
Pair-rule genes that affect engrailed expression
fushi tarazu, even-skipped
Property of anterior and posterior boundaries of parasegments
Boundaries of cell-lineage restriction
Role of segmentation genes
Fix positions of parasegment boundaries
Fix positions of segment boundaries of larval epidermis
Domains of cell-lineage restriction
Compartments
Group of 16 cells in the germarium
Germline cyst
Components of germline cyst
1 oocyte + 15 nurse cells
Cells that envelope germline cyst
Follicle cells
First sign of anterior-posterior polarity of egg
Migration of oocyte and nurse cells from center to posterior end
End with localized translation of Gurken protein
Posterior end
Gurken effect on follicle cells
Induces terminal follicle cells to adopt a posterior fate
Gurken receptor protein
Torpedo
Orientation of microtubules in oocyte after Gurken signaling
Minus ends directed toward interior and plus ends toward exterior
Proteins responsible for oocyte cytoskeleton reorganization
PAR proteins
How is bicoid transported to anterior end?
Microtubules
Maternal-effect mRNA transported to oocyte posterior
Oskar
RNA binding protein needed for localization of oskar and bicoid
Staufen
